Gable top cartons are commonly used for packaging liquid food products such as milk, juices, citrus products and vegetable cocktails. When the product is to be refrigerated, such as in the case of milk, the integrity of the seal is not critical. It is desirable to avoid spillage, but because of the short shelf life and refrigeration of the milk there should not be a practical problem due to spoilage as a result of contaminants entering the carton. It is therefore possible to provide a closure that can be opened without too much difficulty by the consumer.
When the product to be packaged is another product such as orange juice or vegetable juice, it is desirable that it have adequate shelf life without the necessity of refrigeration. If the seal is inadequate, bacteria, molds and yeast may contaminate the product and cause spoilage. Also, if air enters the container it may cause oxidation. It is therefore necessary to provide an extremely strong seal. The entire top is heat sealed, according to present practice, and is also impressed with vertical stake lines, a horizontal stake line, and a central stake point. The result is, however, that the container is not an easy opening carton from the point of view of the average consumer. This defeats one of the main purposes of having a gable top container. Various expedients have been used to try to solve this problem including a weakened severance line, but this has not proven to be entirely satisfactory.